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Detection and Characterization of RB1 Mosaicism in Patients With Retinoblastoma Receiving cfDNA Test.

IMPORTANCE: Plasma cell-free DNA (cfDNA) testing is increasingly used for disease diagnosis and monitoring in retinoblastoma, with RB1 allele fraction in cfDNA actively corresponding to disease status and treatment response. However, while RB1 mosaicism has been reported in retinoblastoma, its clinical implications and potential impact on cfDNA testing remain unclear. OBJECTIVES: To identify RB1 mosaicism using paired plasma and buffy coat (containing lymphocytes, monocytes, granulocytes, and platelets) DNA testing, and to characterize the implications of RB1 mosaicism on cfDNA testing outcomes. DESIGN, SETTING, AND PARTICIPANTS: In this cross-sectional study, participants with retinoblastoma underwent testing with MSK-ACCESS (Memorial Sloan Kettering-Analysis of Circulating cfDNA to Examine Somatic Status), a clinical assay that combines plasma cfDNA and buffy coat genomic DNA sequencing, enabling the detection and differentiation of somatic, heterozygous, and mosaic variants, between July 2020 and April 2024 at the Memorial Sloan Kettering Cancer Center. Mosaic findings from MSK-ACCESS were correlated with those from a subgroup of patients who concurrently underwent testing using the MSK-IMPACT germline assay. Data analysis was performed from April to September 2024. EXPOSURE: RB1 mosaicism in retinoblastoma. MAIN OUTCOMES AND MEASURES: The RB1 variant allele fractions in cfDNA and buffy coat genomic DNA were used to detect RB1 mosaicism. RESULTS: A total of 136 consecutive patients with retinoblastoma (median age at diagnosis, 1.0 year [IQR, 0.4-1.7 years]; 74 [54.4%] female; 67 with bilateral disease and 69 with unilateral disease) who underwent testing with the MSK-ACCESS assay were included. RB1 mosaicism was identified in buffy coat DNA from 20 patients (14.7%), with consistent results detected in all 11 participants tested concurrently by the MSK-IMPACT (Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets) germline assay. Four participants with RB1 mosaicism previously tested negative for germline RB1 variants by external laboratories. Compared with heterozygous participants, participants with RB1 mosaicism had a lower risk of developing bilateral disease (91.7% vs 55.0%, respectively; difference, 36.7% [95% CI, 13.8%-59.6%]; P = .002). In cfDNA, the mosaicism variant was detected both before and after treatment, with variant allele fraction initially decreasing after treatment but then stabilizing at levels consistent with mosaicism, despite the absence of clinical disease. CONCLUSIONS AND RELEVANCE: The accurate detection and quantification of RB1 mosaicism are crucial. RB1 mosaicism should be considered when RB1 variants persist in cfDNA after treatment without evidence of disease; failure to do so may lead to false-positive results and overtreatment in patients with RB1 mosaicism. Identifying RB1 mosaicism may improve patient counseling, inform treatment decisions, and enhance surveillance efforts.

Humans

Bilateral Conversion Risk in Unilateral Retinoblastoma Using Age and Genetic Testing.

IMPORTANCE: Metachronous bilateral conversion in initially unilateral retinoblastoma is uncommon but clinically consequential, potentially requiring intensified treatment and carrying worse prognosis. Clarifying how age at diagnosis refines genetic-risk stratification could enable safer, more efficient surveillance protocols. OBJECTIVE: To estimate the incidence and timing of metachronous bilateral conversion in unilateral retinoblastoma and assess whether age at diagnosis and RB1 testing are associated with bilateral conversion risk. DESIGN, SETTING AND PARTICIPANTS: This was a retrospective cohort study at a tertiary center in Shanghai, China, including 1108 consecutive children with initially unilateral retinoblastoma diagnosed from July 2010 to October 2024 (after exclusions for short follow-up [n = 139], missing data [n = 53], or synchronous bilateral disease [n = 10]). The median (IQR) follow-up was 43.4 (24.2-67.6) months. EXPOSURES: Age at diagnosis and RB1 genetic status/subtypes assessed by next-generation sequencing and multiplex ligation-dependent probe amplification, including penetrance class (high vs low) and mosaic vs germline categorization. MAIN OUTCOMES AND MEASURES: Time to metachronous bilateral conversion; cumulative incidence functions with death as a competing risk; spatial distribution of fellow-eye tumors. RESULTS: Among 1108 patients (median [IQR] age at diagnosis, 22.2 [12.0-31.4] months; 591 [53.3%] male), 24 (2.2%) developed metachronous bilateral disease. At 24 months, cumulative incidence was 2.2% (95% CI, 1.3-3.1) overall. By genetic status, the 24-month cumulative incidence was 24.8% (95% CI, 13.8-35.9) in RB1 variant-positive vs 1.6% (95% CI, 0.0-3.1) in RB1 variant-negative patients. Among RB1 variant-positive patients, risk clustered among those diagnosed before 9 months, whereas no conversions were observed among those diagnosed at older than 9 months. Four RB1 variant-negative patients who were initially diagnosed at notably late ages (20.9, 42.7, 79.6, and 118 months) subsequently converted; these cases likely represent undetected low-level mosaicism, somatic variants below detection thresholds, or rare genomic events not captured by standard sequencing panels. Fellow-eye tumors did not involve macula and showed a nasal-predominant distribution. CONCLUSIONS AND RELEVANCE: The findings in this study suggest that age at diagnosis may refine genetic risk stratification for metachronous bilateral conversion. RB1 variant-positive patients diagnosed at 9 months or later represent a very low-risk subgroup that may warrant surveillance deescalation, while rare late conversions in RB1 variant-negative patients necessitate continued long-term monitoring.

Humans

Genetic Newborn Screening for Retinoblastoma: A Belgian Initiative Baby Detect.

Baby Detect Project, started in September 2022, aimed to create a newborn screening test using targeted next-generation sequencing for all early-onset, treatable, and serious conditions. The elaborated gene panel covers 405 genes, associated with 165 genetic conditions, and includes RB1, linked to retinoblastoma, the only oncological disease tested for. Germline RB1 mutations concern around 50% of all retinoblastoma cases and 100% of the most severe, bilateral cases. Ninety percent of them occur de novo, which delays the diagnosis by about a year with subsequent loss of vision and sometimes the eye itself. Detecting children with germline RB1 mutation at birth would greatly improve functional and anatomic outcomes, limiting invasive treatments and general anesthesias through early childhood. We discuss herein the novel approach of population screening, the rationale for newborn testing for RB1 mutations, the incidence of expected cases, the reliability of the test and its costs. The next step is to move to a nation-scale population; this initiative marks a landmark in retinoblastoma patients' care.

Humans

Novel insights into retinoblastoma: From oncogenic circuitry to precision diagnosis and eye-preserving therapies.

Retinoblastoma (RB) represents the most common primary intraocular malignancy in childhood and stands as a paradigm for translating molecular oncology into precision clinical management. This review synthesizes the comprehensive evolution in the understanding and treatment of RB. First, we deconstruct the intricate oncogenic circuitry that extends far beyond Knudson's classic "two-hit" RB1 inactivation model, describing non-classical MYCN-driven pathogenesis, multi-layered epigenetic reprogramming (including chromatin, RNA and histone changes), and distinct histological subtypes with defined clinical correlates, such as the favorable-prognosis cavitary RB. Single-cell genomics has elucidated the cellular origin from cone precursor cells and intratumoral heterogeneity. Risk stratification has been refined through well-defined classification systems, from the therapy-guiding International Intraocular Retinoblastoma Classification (IIRC) to the comprehensive American Joint Committee on Cancer Tumor-Node-metastasis (AJCC TNM) staging. Furthermore, the diagnostic paradigm has advanced from conventional anatomical imaging to liquid biopsies, enabling non-invasive molecular staging and monitoring via tumor-derived cell-free DNA analysis. Concurrently, the therapeutic landscape has undergone a radical shift, moving from enucleation and external-beam radiotherapy to an era dominated by local sight-preserving strategies. We provide a critical synthesis of the evidence for intravenous chemotherapy and the transformative role of super-selective intra-arterial chemotherapy (IAC), and describe essential randomized controlled trials, technical innovations, and optimized drug regimens. Finally, we explore emerging targeted molecular therapies and future directions. By integrating cutting-edge molecular insights with robust, high-level clinical evidence, this review offers the framework for achieving patient and eye survival as well as vision preservation in children with Retinoblastoma.

Intra-arterial chemotherapy

Bibliometric analysis of retinoblastoma research over the past decade.

BACKGROUND: Retinoblastoma (RB), the most prevalent primary intraocular malignancy in children, has emerged as a model disease for exploring the molecular underpinnings of pediatric cancer. Over the past decade, research in this field has accelerated, propelled by advances in genomics, diagnostic imaging, targeted therapies, and global scientific collaboration. METHODS: This study systematically retrieved RB-related publications from 2015 to 2024 using the Web of Science Core Collection. A total of 4990 articles were included. CiteSpace and VOSviewer were employed to perform bibliometric and visual analyses across multiple dimensions, including countries, institutions, authors, journals, and thematic evolution. RESULTS: The United States and China were identified as the leading contributors, jointly accounting for over 40.55% of all publications. US-based journals led in both publication volume and citation impact, underscoring their global influence. Cluster analysis revealed 4 major research domains: clinical diagnosis, treatment, and prognosis; molecular mechanisms and signaling pathways; gene and protein function studies; and research methodologies and experimental models. CONCLUSION: RB research is transitioning into an era of precision oncology, characterized by molecular subtyping, novel therapeutic targets, and individualized treatment approaches. While diagnostic and therapeutic outcomes have markedly improved in high-income countries, significant disparities persist in low- and middle-income regions due to limited access to early detection and comprehensive care. Future priorities should include the refinement of preclinical models, investigation of drug resistance mechanisms, and promotion of international collaboration to standardize diagnostic and therapeutic strategies. These efforts are critical to improving global outcomes for children with RB.

Retinoblastoma

A functional assay to classify RB1 variants of uncertain significance.

PURPOSE: The RB1 gene encodes the retinoblastoma protein (pRB) playing a major role in cell cycle control, particularly by its interaction with E2F transcription factors. Familial forms of retinoblastoma are caused by germline pathogenic variants in the RB1 gene predisposing to retinoblastoma and other tumors. By analyzing the RB1 gene in patients with retinoblastoma, we found that missense variants often remain variants of uncertain significance (VUS). METHODS: To classify RB1 VUS, we developed a functional assay evaluating their impact on the ability of pRB to inhibit the activity of the E2F1 promoter, with a luciferase reporter gene. A set of 14 pathogenic/likely pathogenic and benign/likely benign RB1 variants was used for validation. RESULTS: We tested 16 VUS detected in patients with retinoblastoma and found that 9 VUS reduced the ability of pRB to inhibit E2F1 promoter. Among them, the (RB1) c.2263T>G p.(Phe755Val) variant showed a reduced level of pRB on Western blot, suggesting a defect in pRB stability. By applying the criterion PS3_moderate of the American College of Medical Genetics and Genomics/Association for Molecular Pathology classification to this functional assay, 5 of the 9 VUS with functional impact could be classified as likely pathogenic. CONCLUSION: This functional assay can improve the molecular diagnosis of retinoblastoma predisposition by a better determination of pathogenic/likely pathogenic RB1 variants.

Humans

Biallelic loss of RB1 in hepatocellular carcinoma as synthetic lethal target for artificial intelligence-guided therapy.

The retinoblastoma (RB1) gene is a critical tumor suppressor that regulates cell cycle progression and genomic stability. Although RB1 alterations have been reported in hepatocellular carcinoma (HCC), the biological and clinical consequences of biallelic RB1 inactivation (RB1-Bi) remain poorly defined. We performed a comprehensive allele-specific genomic analysis of HCC patients from the TCGA-LIHC (n&#x2009;=&#x2009;355) and in-house AMC (n&#x2009;=&#x2009;206) cohorts, collectively comprising the AMC-TCGA discovery cohort. In this combined cohort, RB1-Bi was identified in 14.6% of tumors, was enriched in poorly differentiated HCCs and was independently associated with significantly reduced overall survival (adjusted hazard ratio 3.32, 95% CI 1.93-5.72, p&#x2009;<&#x2009;0.001). Additionally, a deep learning-based histopathology model using hematoxylin and eosin-stained slides (i.e., FR-MIL model) accurately predicted RB1-Bi status (F1 score 84.39% [95% CI, &#xb1;0.02]), making it readily identifiable in routine clinical practice. The prevalence and prognostic impact of RB1-Bi, as well as FR-MIL model performance, were consistent across independent validation cohorts, including advanced-stage tumors and external institutions. High-throughput drug screening in isogenic HCC models revealed that RB1-Bi HCC cells were particularly sensitive to inhibitors targeting mitotic regulators (e.g., AURKA, PLK1, KSP) and DNA damage response pathways (e.g., PARP inhibitors). Synthetic lethal interactions between RB1-Bi and these compounds were demonstrated in vitro and in vivo, and combination treatment with mitotic and PARP inhibitors had synergistic effects with acceptable tolerability. We conclude that RB1-Bi represents a clinically actionable biomarker that identifies a high-risk HCC subtype with specific therapeutic vulnerabilities, offering new opportunities for precision medicine.

Humans

Rb-driven transcription limits its tumour-suppressive effects in breast cancer.

The retinoblastoma protein (Rb) is a tumour suppressor best known for repressing E2F transcription factors and halting cell cycle progression1. In hormone receptor-positive (HR+) breast cancer, CDK4/6 inhibitors activate Rb by preventing its phosphorylation, forming a key component of current endocrine therapy regimens2. How pharmacologically activated Rb remodels chromatin and influences transcription beyond cell cycle arrest remains poorly understood. Here we show that CDK4/6 inhibition induces redistribution of hypophosphorylated Rb to promoters and enhancers. Although Rb predictably binds to cell cycle gene promoters to repress transcription, at other sites, it unexpectedly promotes expression of oestrogen-responsive genes by integrating into oestrogen receptor (ER)-rich transcriptional hubs. CDK4/6 inhibition enhances ER target gene expression in breast cancer cells, patient-derived xenografts and clinical HR+ breast cancer samples in an Rb-dependent manner. This reprogramming is mediated in part by KDM5A, whose interaction with Rb contributes to gene regulation at these loci. Critically, components of this Rb-driven ER transcriptional program are pro-proliferative. In endocrine-sensitive tumours, this effect&#xa0;can be neutralized with anti-oestrogen therapy, explaining therapeutic synergy. In endocrine-resistant settings such as ESR1-mutant breast cancer, the program persists, limiting the&#xa0;therapeutic efficacy&#xa0;of&#xa0;CDK4/6 inhibition. These findings reframe Rb as a dual-function transcriptional regulator that, although enforcing cell cycle arrest, can also activate programs that counteract its tumour suppressor function.

Humans

Blood-based proteomic profiling reveals context-dependent changes in BCL2-associated signaling during taxane therapy in breast cancer patients.

The quality of life for many cancer survivors is compromised due to severe, long-lasting side effects of chemotherapy. As part of a pilot, prospective, non-interventional study to examine the side effects of chemotherapy in breast cancer patients, we examined the change in protein expression in blood collected from patients before and after treatment with taxanes for 12&#x2009;weeks. Protein expression was measured with reverse phase proteomic arrays (RPPA), which revealed divergent changes in apoptosis, senescence, and calcium signaling-related proteins depending on treatment setting (neoadjuvant vs. adjuvant). The largest change identified was BCL2 (B-cell lymphoma 2), a founding member of the BCL2 family of proteins that regulate apoptosis. Other proteins regulated by BCL2, including RB1 (retinoblastoma protein 1) and NLRP3 (NLR family pyrin domain containing 3) changed significantly over the course of treatment. These differences are consistent with intracellular calcium signaling dysregulation and activation of stress-response pathways that overlap with senescent-associated secretory phenotype (SASP)-like signaling, which has been implicated in cancer recurrence. To contextualize these observations, we generated Kaplan-Meier survival curves using publicly available proteomics data from The Cancer Proteome Atlas (TCPA). This work aims to demonstrate how blood-based proteomics can serve as a non-invasive method to monitor systemic physiological shifts during cancer therapy, offering a framework for generating hypotheses about chemotherapy timing and long-term outcomes.

Humans

The genomic landscape of HER2 negative metastatic breast cancer with loss of estrogen and progesterone receptors.

INTRODUCTION: Loss of estrogen receptor (ER) and/or progesterone receptor (PR) might occur during the metastatic progression of ER positive and HER2 negative (ER+/HER2-) breast cancer (BC), but the underpinning molecular alterations remain elusive. We explored the genomic context of HER2- tumors with ER and/or PR loss to investigate potential drivers and actionable alterations that might help personalize treatment of ER+/HER2- BC. METHODS: We accessed data from metastatic HER2- BC included in the MSK-2018 dataset to compare outcome, tumor characteristics and genomic alterations of BC with loss of ER (ER+/-, n&#xa0;=&#xa0;66) to those maintaining ER positivity (ER+/+, n&#xa0;=&#xa0;364) or ER negativity (ER-/-, n&#xa0;=&#xa0;50). We also compared metastatic ER+/+ BC with loss of PR (PR+/-, n&#xa0;=&#xa0;111) to those maintaining PR positivity (PR+/+, n&#xa0;=&#xa0;192) or PR negativity (PR-/-, n&#xa0;=&#xa0;41). RESULTS: In line with previous reports, ER+/-&#xa0;BC was associated with aggressive clinico-pathological characteristics and poor outcome. ER+/-&#xa0;BC showed significantly higher frequency of TP53 and RB1 mutations and lower frequency of PIK3CA and GATA3 mutations compared to ER+/+. ER+/-&#xa0;or PR+/-&#xa0;status was mutually exclusive with ESR1 mutations and was associated with a significantly higher tumor mutational burden. Moreover, ER+/-&#xa0;BC were enriched in driver alterations in the genes of the Notch and Retinoblastoma pathways and showed a significantly lower frequency of level 1 actionable alterations according to OncoKB. CONCLUSIONS: Loss of ER and/or PR may identify a distinct evolutionary trajectory of ER+/HER2- metastatic progression, largely non-overlapping with ESR1-mutant endocrine resistance. Further studies on matched primary and metastatic samples are warranted.

Humans

Elucidating the roles of SOD3 correlated genes and reactive oxygen species in rare human diseases using a bioinformatic-ontology approach.

Superoxide Dismutase 3 (SOD3) scavenges extracellular superoxide giving a hydrogen peroxide metabolite. Both Reactive Oxygen Species diffuse through aquaporins causing oxidative stress and biomolecular damage. SOD3 is differentially expressed in cancer and this research utilises Gene Expression Omnibus data series GSE2109 with 2,158 cancer samples. Genome-wide expression correlation analysis was conducted with SOD3 as the seed gene. Categorical SOD3 Pearson Correlation gene lists incrementing in correlation strength by 0.01 from &#x3c1;&#x2265;|0.34| to &#x3c1;&#x2265;|0.41| were extracted from the data. Positively and negatively SOD3 correlated genes were separated for each list and checked for significance against disease overlapping genes in the ClinVar and Orphanet databases via Enrichr. Disease causal genes were added to the relevant gene list and checked against Gene Ontology, Phenotype Ontology, and Elsevier Pathways via Enrichr before the significant ontologies containing causal and non-overlapping genes were reviewed with a literature search for possible disease and oxidative stress associations. 12 significant individually discriminated disorders were identified: Autosomal Dominant Cutis Laxa (p = 6.05x10-7), Renal Tubular Dysgenesis of Genetic Origin (p = 6.05x10-7), Lethal Arteriopathy Syndrome due to Fibulin-4 Deficiency (p = 6.54x10-9), EMILIN-1-related Connective Tissue Disease (p = 6.54x10-9), Holt-Oram Syndrome (p = 7.72x10-10), Multisystemic Smooth Muscle Dysfunction Syndrome (p = 9.95x10-15), Distal Hereditary Motor Neuropathy type 2 (p = 4.48x10-7), Congenital Glaucoma (p = 5.24x210-9), Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome (p = 3.77x10-16), Classical-like Ehlers-Danlos Syndrome type 1 (p = 3.77x10-16), Retinoblastoma (p = 1.9x10-8), and Lynch Syndrome (p = 5.04x10-9). 35 novel (21 unique) genes across 12 disorders were identified: ADNP, AOC3, CDC42EP2, CHTOP, CNN1, DES, FOXF1, FXR1, HLTF, KCNMB1, MTF2, MYH11, PLN, PNPLA2, REST, SGCA, SORBS1, SYNPO2, TAGLN, WAPL, and ZMYM4. These genes are proffered as potential biomarkers or therapeutic targets for the corresponding rare diseases discussed.

Humans

Cyclin-dependent kinase 4 and 6 inhibitors and the breast cancer immune ecosystem: immune remodeling, resistance, and therapeutic reprogramming.

Cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6 inhibitors) combined with endocrine therapy have become a therapeutic backbone for hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer, yet durable disease control is frequently limited by intrinsic and acquired resistance. Canonical tumor-cell mechanisms, including retinoblastoma-pathway escape, cyclin E-cyclin-dependent kinase 2 (CDK2) activation, endocrine adaptation, and phosphoinositide 3-kinase (PI3K)-AKT-mechanistic target of rapamycin (mTOR) signaling, explain only part of this failure because they do not fully capture dynamic immune and stromal remodeling. Preclinical and translational studies indicate that early CDK4/6 inhibition can enhance antigen presentation, activate interferon-related programs, restrain regulatory T cells, and promote a T-cell-inflamed state. These effects are conditional and may not persist during prolonged treatment. Sustained therapy can instead drive heterogeneous resistant niches characterized by stromal remodeling, myeloid recruitment, checkpoint adaptation, and T-cell dysfunction. This immune-state dependence provides a rationale for immune checkpoint blockade, although clinical combinations have shown mixed efficacy and clinically relevant hepatic, pulmonary, and hematologic toxicities. Sequential or lead-in strategies therefore warrant prospective evaluation. Oxidative phosphorylation (OXPHOS) and redox adaptation may sustain selected resistant states and expose context-dependent ferroptotic vulnerabilities. Ferroptosis may connect tumor-cell killing with immune regulation, whereas nanomedicine may improve tumor-selective delivery. Both strategies remain largely preclinical and require further evaluation of pharmacokinetics, biodistribution, toxicity, manufacturability, and immune-cell safety. This Review distinguishes intrinsic from acquired resistance across interpatient, intratumoral, spatial, and temporal dimensions. It integrates tumor-cell escape with cytokine, immune, stromal, vascular, and metabolic remodeling and summarizes emerging therapeutic strategies. We further propose a candidate biomarker-informed framework that integrates genomic profiling, spatial immune architecture, circulating biomarkers, T-cell receptor (TCR) dynamics, transcriptomic and single-cell analyses, artificial intelligence (AI)-assisted multimodal integration, and longitudinal sampling. This framework is intended to support biomarker development and prospective trial design rather than current clinical decision-making, providing a translational basis for testing state-informed and sequence-aware therapeutic strategies.

Humans

A Highly Abnormal Clone in a Pediatric Patient with B-Lymphoblastic Leukemia.

We present a case of a 14-year-old male who presented with loss of appetite, nosebleeds, and fatigue. He visited the clinic, and bone marrow studies were suggested. Bone marrow, core biopsy and clot section showed hypercellularity (80-90%) with sheets of blasts with suspicion of precursor B acute lymphoblastic leukemia (B-ALL). Chromosome analysis of 20 trypsin-Giemsa banded metaphase spreads showed an abnormal male composite karyotype described as 45~47,XY,+1,add(1)(p13),add(1)(q10),add(7)(q36), add(12)(q24.1),der(12)(p13->q24.1::12p13.2->12p13.1::12q24.1->12qter),-13,-15,add(16)(p13.1),-17,+1~3 mar[cp17]/46,XY[3]. Fluorescence in situ hybridization (FISH) was performed, showing one diminished signal for ETV6 in 99% [198/200] of the nuclei examined with the ETV6/RUNX1 probe. ETV6 break-apart probe on interphase nuclei showed one fusion (normal) and one green signal (5'ETV6) in 92% [184/200] of the nuclei. Metaphase FISH with the ETV6 BA probe showed one fusion on the normal chromosome 12 and one green signal (5'ETV6) on the long arm of the derivative chromosome 12. Additionally, metaphase FISH showed a 1q25 signal (green) in one abnormal copy of chromosome 1 as well as 1p36 signal (orange) in the additional abnormal copy of chromosome 1, and a retinoblastoma (Rb) signal (13q14.2) on the derivative chromosome 7. In light of these studies, the karyotype was described as a highly complex karyotype associated with genomic instability and a poor prognosis.

Journal Article

Impact of Genomic Mutations on the Transcriptional Pathways and Tumor Microenvironment Landscape of Localized Early Prostate Cancer.

BACKGROUND: The management of intermediate-risk early prostate cancer (PCa) is challenging due to the difficulty in distinguishing indolent from aggressive tumors. This study explores the association between genomic alterations and the tumor and its microenvironment (TME) and implications for disease progression. METHODS: We performed multi-omic profiling in a cohort of 53 localized PCa using targeted sequencing, transcriptional, and proteomic spatial profiling. RESULTS: Somatic mutations and copy number alterations in RB1 (21%), PTEN (18%), and TP53 (9%) were identified. Kaplan-Meier analysis revealed that alterations in the RB and Cell Cycle pathways, particularly aberrations in PTEN, TP53, or RB1, were associated with shorter biochemical recurrence-free survival (p&#x2009;<&#x2009;0.001). Spatial proteomic analysis demonstrated a complex immune landscape in patients with mutations. The tumor compartment demonstrated higher expression of immune checkpoint markers, T-cell activation proteins, and proliferation markers; and a TME that is enriched with CD8&#x2009;+&#x2009;T cells and antigen-presenting cells, but also with immunosuppressive M2 macrophages, suggesting adaptive immune resistance. CONCLUSIONS: Our analysis demonstrates that genomic alterations in PTEN, TP53, or RB1 are not only prognostic for poor outcomes but are also associated with a unique, immunologically complex TME in this Brazilian cohort.

Humans

Mouse Prkar1a haploinsufficiency leads to an increase in tumors in the Trp53+/- or Rb1+/- backgrounds and chemically induced skin papillomas by dysregulation of the cell cycle and Wnt signaling.

PRKAR1A inactivation leads to dysregulated cAMP signaling and Carney complex (CNC) in humans, a syndrome associated with skin, endocrine and other tumors. The CNC phenotype is not easily explained by the ubiquitous cAMP signaling defect; furthermore, Prkar1a(+/-) mice did not develop skin and other CNC tumors. To identify whether a Prkar1a defect is truly a generic but weak tumorigenic signal that depends on tissue-specific or other factors, we investigated Prkar1a(+/-) mice when bred within the Rb1(+/-) or Trp53(+/-) backgrounds, or treated with a two-step skin carcinogenesis protocol. Prkar1a(+/-) Trp53(+/-) mice developed more sarcomas than Trp53(+/-) mice (P < 0.05) and Prkar1a(+/-) Rb1(+/-) mice grew more (and larger) pituitary and thyroid tumors than Rb1(+/-) mice. All mice with double heterozygosity had significantly reduced life-spans compared with their single-heterozygous counterparts. Prkar1a(+/-) mice also developed more papillomas than wild-type animals. A whole-genome transcriptome profiling of tumors produced by all three models identified Wnt signaling as the main pathway activated by abnormal cAMP signaling, along with cell cycle abnormalities; all changes were confirmed by qRT-PCR array and immunohistochemistry. siRNA down-regulation of Ctnnb1, E2f1 or Cdk4 inhibited proliferation of human adrenal cells bearing a PRKAR1A-inactivating mutation and Prkar1a(+/-) mouse embryonic fibroblasts and arrested both cell lines at the G0/G1 phase of the cell cycle. In conclusion, Prkar1a haploinsufficiency is a relatively weak tumorigenic signal that can act synergistically with other tumor suppressor gene defects or chemicals to induce tumors, mostly through Wnt-signaling activation and cell cycle dysregulation, consistent with studies in human neoplasms carrying PRKAR1A defects.

Animals

Mechanism of histone demethylase KDM5A in osteoporotic fracture healing through epigenetic regulation of the miR-495/SKP2/Runx2 axis.

BACKGROUND: Osteoporosis represents a salient metabolic bone disorder. Histone demethylase plays a vital role in bone development and homeostasis. This study explored the mechanism of histone demethylase KDM5A affecting osteoporotic fracture healing via the miR-495/SKP2/Runx2 axis. METHODS: The murine model of osteoporotic fracture was established. The bone mineral density, maximum elastic stress, and maximum load were tested. The relative trabecular bone volume, bone trabecular thickness, and trabecular number at the proximal end of tibia were detected. The histopathological changes of femur tissues and bone microstructure were observed. Expressions of KDM5A and osteogenic factors were detected. The cell proliferation, alkaline phosphatase activity, and calcified nodules were measured. The binding relationships between KDM5A and miR-495 promoter, and miR-495 and SKP2 were verified. The interaction between SKP2 and Runx2 was detected. The ubiquitination level of Runx2 and the stability of Runx2 protein were detected. RESULTS: KDM5A was highly expressed in the murine model of osteoporotic fracture. Interference of KDM5A expression facilitated fracture healing in osteoporotic mice. KDM5A downregulated miR-495 expression by promoting the H3K4me3 methylation of the miR-495 promoter. Inhibition of miR-495 reversed the effect of KDM5A silencing on osteoblast proliferation, differentiation, and mineralization. miR-495 facilitated osteoblast proliferation, differentiation, and mineralization by targeting SKP2. SKP2 suppressed Runx2 expression through ubiquitination degradation. Inhibition of Runx2 reversed the promoting effect of SKP2 silencing on osteogenic differentiation. CONCLUSION: KDM5A attenuated the inhibition of miR-495 on SKP2 and promoted the ubiquitination degradation of Runx2 protein by SKP2, thereby repressing osteoblast differentiation and retarding osteoporotic fracture healing.

Animals